Carbonylation reactions are known in the art. For instance, in EP-A-0,495,547 several examples are disclosed wherein olefins are converted into (thio)esters, acids, anhydrides, and amides, etc., depending on the nature of the coreactant. Other examples on the synthesis of aldehydes; ketones; carboxylic acids; esters; amides and other carboxylic acid derivatives; lactones; lactams and related N-heterocycles as well as background references can be found in "Carbonylation" by H M Colquhoun, D J Thompson and M V Twigg (Plenum press 1991). Typically, the rate of reaction is in the order of up to several hundreds moles product per mol catalyst (based on the metal) per hour. In case of internal unsaturation, the rate of reaction is several orders lower. In other words, either relatively large amounts of catalyst are required or prolonged reaction times are involved.